Display device having liquid crystal layer and switchable optical layer

Abstract

A display device including a first electrode, a liquid crystal layer positioned under and connected to the first electrode, a second electrode and a switchable optical layer. The switchable optical layer includes either a transparent state or a non-transparent state and is electrically switchable between the transparent state and the non-transparent state. The non-transparent state is selectively emissive state. The switchable optical layer is positioned above and connected to the second electrode. A third electrode is positioned between the liquid crystal layer and the switchable optical layer.

1. A display device comprising:
 a first electrode; 
 a liquid crystal layer positioned under and connected to the first electrode; 
 a second electrode; 
 a switchable optical layer, having in use either a transparent state or a non-transparent state and being electrically switchable between the transparent state and the non-transparent state, wherein the non-transparent state is a selectively emissive state, and wherein the switchable optical layer is positioned above and connected to the second electrode; 
 a plurality of pixel switches in physical contact with and electrically connected to the second electrode; and 
 a third electrode positioned between the liquid crystal layer and the switchable optical layer, 
 wherein the second electrode is a first pixellated electrode connected to the switchable optical layer and comprises a first plurality of first distinct electrodes, wherein the third electrode is a second pixellated electrode connected to the switchable optical layer and comprises a plurality of second distinct electrodes, and wherein each one of the first distinct electrodes opposes an associated second distinct electrode across the switchable optical layer, and further wherein the plurality of pixel switches are positioned below the second electrode, such that each pixel switch is connected to one of the plurality of first distinct electrodes; 
 wherein the first electrode is electrically connected to a constant voltage supply; and 
 wherein the third electrode is electrically connected to the constant voltage supply during the non-transparent state. 
 
     
     
       2. The display device of  claim 1 , wherein the third electrode is shared by the liquid crystal layer and the switchable optical layer. 
     
     
       3. The display device of  claim 1 , wherein at least one of the first or third electrodes is pixellated and has associated pixel switches. 
     
     
       4. The display device of  claim 1 , wherein the first electrode is a unitary transparent electrode. 
     
     
       5. The display device of  claim 1 , wherein the third electrode is transparent. 
     
     
       6. The display device of  claim 1 , wherein the second electrode is reflective. 
     
     
       7. The display device of  claim 1 , further comprising control means configured, in a first mode, to maintain the second distinct electrodes of the third electrode at the same voltage and, in a second mode, to maintain each second distinct electrode of the third electrode at the same voltage as its associated first distinct electrode of the second electrode. 
     
     
       8. The display device of  claim 1 , wherein at least a portion of the plurality of pixel switches are configured to supply a voltage or current to the second electrode to enable the switchable optical layer to emit light. 
     
     
       9. The display device of  claim 1 , wherein the second and third electrodes are configured to be electrically connected in parallel during the transparent state. 
     
     
       10. A mobile device comprising:
 a power supply; and 
 a display device including:
 a first electrode; 
 a liquid crystal layer positioned under and connected to the first electrode; 
 a second electrode; 
 a switchable optical layer, having in use either a transparent state or a non-transparent state and being electrically switchable between the transparent state and the non-transparent state, wherein the non-transparent state is a selectively emissive state, and wherein the switchable optical layer is positioned above and connected to the second electrode; 
 a plurality of pixel switches in physical contact with and electrically connected to the second electrode; and 
 a third electrode positioned between the liquid crystal layer and the switchable optical layer, 
 
 wherein the second electrode is a first pixellated electrode connected to the switchable optical layer and comprises a first plurality of first distinct electrodes, wherein the third electrode is a second pixellated electrode connected to the switchable optical layer and comprises a plurality of second distinct electrodes, and wherein each one of the first distinct electrodes opposes an associated second distinct electrode across the switchable optical layer, and further wherein the plurality of pixel switches are positioned below the second electrode, such that each pixel switch is connected to one of the plurality of first distinct electrodes; 
 wherein the first electrode is electrically connected to a constant voltage supply; and 
 wherein the third electrode is electrically connected to the constant voltage supply during the non-transparent state. 
 
     
     
       11. The mobile device of  claim 10 , wherein the third electrode is shared by the liquid crystal layer and the switchable optical layer. 
     
     
       12. The mobile device of  claim 10 , wherein at least one of the first or third electrodes is pixellated and has associated pixel switches. 
     
     
       13. The mobile device of  claim 10 , wherein the first electrode is a unitary transparent electrode. 
     
     
       14. The mobile device of  claim 10 , wherein at least a portion of the plurality of pixel switches are configured to supply a voltage or current to the second electrode to enable the switchable optical layer to emit light. 
     
     
       15. The mobile device of  claim 10 , wherein the second and third electrodes are configured to be electrically connected in parallel during the transparent state.